In a system such as a data center, in which many computers are deployed, a network technique of efficiently connecting the computers is required. In such a system, a central control type network configuration is more preferable than a distribution control type network configuration such as the Internet. The central control type network system is hereinafter referred to as “network central control system”. For example, the network central control system utilizing Openflow (refer to http://www.openflowswitch.org/) has been known.
FIG. 1 is a diagram schematically showing a configuration of a typical network central control system. The network central control system includes a network central control section 10 (management server) that manages and controls a network NET in a central manner. In the network NET, a plurality of switches 20 are arranged (for example, 20-0 to 20-4 are shown in this FIG.). The adjacent switches 20 are connected to each other through a link LN. The network central control section 10 is connected to each of the switches 20 through a control link LC.
Each of the switches 20 has a function of transferring a packet. For example, each of the switches 20 has a transfer table. The transfer table represents correspondence between flow identification data and packet transfer destination. The flow identification data includes, for example, packet header data and an input port. Each of the switches 20 can transfer the packet received from the input port to the transfer destination by referring to the transfer table.
The network central control section 10 has a function of determining and setting a packet transmission route in the network NET. It is assumed that one terminal starts to transmit a packet of a new flow. When a first packet reaches a first switch 20 (for example, switch 20-0), the switch 20-0 does not recognize the transfer destination of the received packet. Thus, the switch 20-0 (request source switch) transmits a route setting request REQ relating to the new flow to the network central control section 10 through the control link LC. In response to the route setting request REQ, the network central control section 10 determines (designs) the transmission route of the packet belonging to the new flow.
When the transmission route is determined, the network central control section 10 transmits route indication data INS to each of the switches 20 (target switches) on the determined transmission route through the control link LC. The route indication data INS is used to instruct the target switches 20 to transfer the packet belonging to the flow along the determined transmission route. The target switch 20 receives the route indication data INS and sets its transfer table according to the route indication data INS. After that, each of the switches 20 on the transmission route can transfer a packet belonging to the flow without making an inquiry to the network central control section 10.
In a case of Openflow, “Openflow Controller” corresponds to the network central control section 10, and “Openflow Switch” corresponds to the switch 20. By using “Secure Channel” of Openflow, the above-mentioned transfer table can be set.
Generally known techniques related to verification in the Internet are as follows.
Patent Literature 1 discloses a network quasi testing device. The quasi testing device receives verification data from a monitor that monitors a transmission route, and transmits the verification data to an actual device connected to the transmission route or a quasi device that represents the actual device in a quasi manner. The quasi testing device converts a destination address A for the verification data, which is destined for the actual device, into an address of the quasi device, to involve the destination address A before the conversion in the verification data. Then, the quasi testing device converts a source address for data returned from the quasi device into the original destination address A.
Patent Literature 2 discloses a quasi network switch testing device. The quasi network switch testing device includes a plurality of transmission/reception ports, a frame control section, a control frame generating section, and a data frame generating section. A plurality of tested devices are connected to the plurality of transmission/reception ports. The frame control section relays a frame between the plurality of transmission/reception ports. The control frame generating section generates a quasi control frame, and transmits the generated quasi control frame from the transmission/reception ports. The data frame generating section generates an arrival confirming data frame, and transmits the generated arrival confirming data frame from the transmission/reception ports.